Currently, an estimated 33.6 million Americans, 80% of which are women, have osteopenia, a precursor of osteoporosis typified by resorptive bone loss. Although the risk of bone fractures is significantly greater in patients with osteoporosis compared to osteopenia, the larger numbers of Americans with osteopenia make this group clinically more significant for risk for fracture. Risk factors for osteopenia include menopause, nutrition and extreme exercise. Current treatments include dietary supplements such as calcium and vitamin D, antiresorptive drugs, estrogen, selective estrogen receptor modulators, bisphonate drugs, calcitonin and anabolic drugs. However, the majority of these treatments have significant side effects or are not suitable for long-term administration.
Bone density is determined by both osteoclastic and osteoblastic activity. Although domination of osteoclastic over osteoblast proliferation/differentiation will result in net bone loss, some osteoclast activity is required for bone replacement and maintenance of normal density. Since endogenous hyaluronan has effects on both osteoclast and osteoblast function and since this is dependent in part upon its molecular weight, it would be difficult to predict the effects of exogenously administered hyaluronan on bone density, particularly since serum and tissue hyaluronidases could theoretically cleave administered hyaluronan to produce an abundance of fragments with osteoclast-activating properties. However, the precise mechanisms by which endogenous hyaluronan effects bone physiology are currently incompletely understood.
There is no teaching in the art of a method for preventing, slowing, attenuating, mitigating, and/or ameliorating the resorptive loss of bone in a vertebrate subject, the method comprising the step of administering a composition comprising a therapeutically effective amount of an exogenous hyaluronan to the subject. The instant invention provides such a method.